基于短舱外伸翼面的倾转旋翼机回转颤振抑制机理研究

In order to achieve the required whirl flutter stability margins, present tiltrotor aircraft used small aspect ratio wing with thick airfoils incurs a loss on cruise efficiency. The additional active and passive control methods acting on tilting rotor and main wings result in the structural weight penalties and design difficulties increasing, which limit the development of heavy tiltrotor aircraft. In this project, the normal whirl flutter depressing idea is broken and the novel depressing approach is focused on pylon outboard wing extensions. Based on multibody dynamics with unsteady aerodynamics and free wake considerations, a tiltrotor-pylon-wing extensions-main wing aeroelastic coupled math model is developed to research the suppressing mechanism of wing extensions on tiltrotor aircraft whirl flutter with auxiliary wind tunnel model test. Through the researching, the aeroelastic dynamical behavior and dynamic stability affected by parameters of wing extensions in airplane forward flight will be explored, which can be used to design a higher aspect ratio wing with thiner airfoils to achieve the prupose of increasing the whirl flutter margins and cruise efficiency at the same time. Finally, the efficient academic analysis method to the tiltrotor aircraft achieved through the project will have the important significance to develop scientific and technical level of our national aviation in rotor aircrafts fields.

当前倾转旋翼机以牺牲巡航效率为代价采用厚翼型加小展弦比机翼以确保回转颤振临界速度，基于现有设计方案对主机翼和旋翼所采取的主被动控制措施会付出额外的重量代价并提高设计难度，限制了倾转旋翼机的进一步大型化。本项目突破常规的思路，不再拘泥于已有的控制措施，拟利用非定常气动力和动态自由尾迹模型和多体动力学方法，建立倾转旋翼/短舱/外伸翼面/主机翼气动弹性耦合分析模型，结合风洞试验，开展短舱外伸翼面对倾转旋翼机回转颤振的抑制机理研究。通过本项目的机理研究，掌握短舱外伸翼面对倾转旋翼机气动弹性耦合的影响程度及分析方法，了解其设计参数对气弹稳定性的影响规律，用于提高机翼展弦比并降低翼型厚度，达到同时提高倾转旋翼机的巡航效率和前飞速度的目的，以充分发挥倾转旋翼机的技术潜力。本项目可以为我国开展倾转旋翼技术研究提供有效的动力学分析方法和理论基础，对提高我国旋翼飞行器的设计水平具有重要指导意义。

本项目建立了倾转旋翼/短舱/外伸翼面/主机翼气动弹性耦合分析模型，结合风洞试验，开展外伸小翼对回转颤振抑制的效果及设计参数的影响规律研究。通过计算与实验对比分析，所建立的理论分析方法与实验结果吻合度良好，验证了所建立分析模型的可靠性以及短舱外伸小翼提高倾转旋翼机的回转颤振边界速度的有效性。采用倾转短舱外伸小翼具有抑制倾转旋翼机回转颤振和提升巡航效率的潜力，研究成果可以为我国开展倾转旋翼技术研究提供有效的动力学分析方法和理论基础，对提高我国旋翼飞行器的设计水平具有参考意义。